Add Maximum Subarray in Tcl (#5069)

Author: pascalecu

archive/t/tcl/maximum-subarray.tcl

@@ -0,0 +1,39 @@
+proc usage {} {
+	puts stderr {Usage: Please provide a list of integers in the format: "1, 2, 3, 4, 5"}
+	exit 1
+}
+
+proc parseList {s} {
+	set tokens [split [string trim $s] ","]
+	if {[llength $tokens] < 1} { usage }
+
+	set result {}
+
+	set result {}
+	foreach token $tokens {
+		set t [string trim $token]
+		if {$t eq "" || [catch {expr {int($t)}} val]} usage
+		lappend result $val
+	}
+	return $result
+}
+
+proc maximumSubarraySum {numbers} {
+    if {[llength $numbers] == 0} { return 0 }
+
+    set currentSum [lindex $numbers 0]
+    set maxSum $currentSum
+
+    for {set i 1} {$i < [llength $numbers]} {incr i} {
+        set val [lindex $numbers $i]
+        set currentSum [expr {max($val, $currentSum + $val)}]
+        set maxSum [expr {max($maxSum, $currentSum)}]
+    }
+
+    return $maxSum
+}
+
+if {$argc != 1} { usage }
+
+set numbers [parseList [lindex $argv 0]]
+puts [maximumSubarraySum $numbers]